Signal system



W. D. LINDSEY 2,123,357

smmz. SYSTEM Filed octl 11, 1933 3 Sheets-Sheet l INVENTQR a W BY ATTORNEY W. D. LINDSEY SIGNAL SYSTEM Filed Oct. 11, 1933 3 Sheets-Sheet 2 W. D. LINDSEY 2,121,357

SIGNAL SYSTEM Filed Oct. .TLl, 1933 5 Sheets-Sheet 3 dg/vmm;

M/iLL v NOR/W941. v

7150 Nor/larunrep Patented June 21, 1938 STATES urrs PATE

SIGNAL SYSTEM Application October 11, 1933, Serial nmssaosz 1 Claim. (01.1'77-35 5) The invention herein disclosed relates to an electrical signal system for indicating the existence of several different conditions and in par ticular, the invention appertains to the operation, over a single pair of transmission lines, of various signals at a remote point, each signal having a different designated significance.

In certain signal systems, for example protective signal systems for property, it is desirable to indicate at a remote point not only the existence of a condition detrimental to the protected property but also a condition which would render the system ineffective to effectuate the actuation of the remote warning signal upon the existence of the condition against which the property is protected. Such an arrangement is particularly desirable in connection with automatic warning systems as, for example, a fire warning system. In such a system, the remote point is preferably the fire engine house serving the locality in which the property to be protected is located. 'Ihe'signal to indicate the existence of a fire may be either audible or visual or both. In addition a distinctly different signal either audible, visual or both, should be used to indicate a condition which would render the system ineffective to effectively operate ortransmit a signal upon the existence of a fire at the property served by the system.

By this invention, several independent electrical signals are actuatedat a remote point over a supervised transmission line made up of a single pair of wires. One signal may indicate the existence of some undesirable condition in a protected property, and another signal may indicate the failure or breakdown of the protective system and in additionanother signal may be provided which is actuated upon the inability of the transmission line to transmit the variations in energy necessary for the actuation of the warning signal and the other trouble signals. In accordance with the invention, a closed electrical circuit is utilized in conjunction with electrically actuated signals and means operative upon open- .ing the circuit to effect the operation of one particular signal and operative upon shunting a portion of the circuit to effect the operation of another signal and operative upon successively opening and closing the circuit to effect the operation of a third signal. When this circuit is used in a protective signal system for protecting property, the signal operated by opening the circuit indicates trouble with the transmission line and the other signals indicate the existence of the condition which is undesirable on the protectecllproperty and the inability of the system to function due to a defect in the portion of the system on the protected property.

In one form, the invention is embodied in a system for signaling the fire department upon the existence of a fire or abnormal thermal conditions on property in connection with which the system is used. Such a system may include as a portion thereof an automatic fire detecting system such as that disclosed in the copending application of William D. Lindsey, Serial No. 687,278, filed August 29, 1933, for Warning system, a code transmitter which upon actuation effects a circuit closer in accordance with a' definite code, and another transmitter which actuates a circuit closer intermittently. The former code transmitter is utilized for effecting the production of electrical impulses in accordance with a predetermined code and thus effecting the operation of an audible signal in accordance with the code which definitely locates the property on which the abnormal thermal conditions exist. The latter transmitter is operative. to effect a series of intermittent impulses. In the case where the signal system transmits a signal directly to a fire house ofzthe municipal fire department the impulses formed by the actuation of the transmitters are transmitted over a transmission line to the fire engine house, which transmission line consists of a single pair of wires; Locatedv in the fire engine house there is a series of relays which are interconnected and mutually dependent in their operation. One of these relays constitutes a part of a closed electrical circuit which includes a source of electrical energy, the relay, and the transmission line connecting the property equipped with the system and the fire engine house. The circuit closer of the code transmitter at the protected property shunts a portion of this circuit, and the circuit closing elements of the other transmitter successively opens and closes this circuit. Theremaining relays of the electrically actuated means for effecting the operation of the trouble signals are interconnected with this relay and depend upon the operation of this relay for the energization thereof. When the circuit opens and remains open, the relay included as a part thereof becomes deenergized and effects the operation of other relays which in turn control particular signals. When the circuit is successively opened and closed, the relay in the circuit is successively deenergized and reenergized. This action through the interconnection of the other relays effects the operation of another independent and distinctly different as this would result in a jumble of codes.

signal. both.

When the code transmitter operates to shunt a portion of the closed circuit, it cuts out a certain amount of resistance and effects the operation of a normally inoperative relay included in the closed circuit. This normally inoperative relay operates in accordance with the impulses set up by the intermittent shunting of a portion of the closed circuit. The relay effects the operation of an audible and visual signal, the audible signal being operated in accordance with the action of the code transmitter which is reproduced in the relay contained in the closed circuit.

The fire system on the protected property may be manually or automatically operated. The manual operation effects the operation of the code transmitter. The operation of the same or a similar transmitter is effected automatically by the automatic system in the event of the existence of abnormal thermal conditions. In the event of a condition existing in that portion of the system on the protected property which would render the system unable to operate eifectively, the intermittently actuated transmitter is operated thus effecting the operation of a signal at a remote point which indicates that the portion of the system on the protected property is inoperative for the purpose intended. The various parts of the system are thus efiectively supervised and continuous protection for the property on which the system is utilized is assured.

Where two or more distinctly different and separated properties are to be protected by systems of this type, it is essential that under no conditions can the transmitters of two or more systems have simultaneous connection with the common audible signal for reproducing the code, The systems are therefore interconnected and include electrically actuated means for giving preferential control of the audible signal to the several systems in accordance with their rating as fire hazards.

Two such interconnected systems are illustrated in the accompanying drawings in which the systems and their interconnection are illustrated diagrammatically by a line drawing in Fig. 1 and by an across-the-line diagram in Figs. 2 and 3 and these systems are described in detail below. From this illustration and description a clearer understanding of the invention may be had.

The drawings illustrate two interconnected protective systems YY and ZZ. In the system ZZ, the fire detecting circuit located on the protected property is an electrically supervised automatically operative circuit. This circuit includes a battery I as a source of current and a fire relay 2 one side of which is connected to the positive side of the battery by a conductor Al. The other side of the fire relay 2 is connected through a conductor A2 to a supervisory relay 3 which is connected in series with one end of an element A3 of a fire detecting cable 4 constructed as disclosed and described in the copending application Serial No. 352,624, filed April 5, 1929, for Cable and method of producing the same. The other end of the element A3 is connected by a conductor A4 to one end of a resistance 4. The other end of the resistance is connected by a conductor A5 to the end of an element A6 of the fire detecting cable corresponding to the end of the element A3 to which the conductor A4 is con- The signals may be visual, audible or nected. The end of the element A6 corresponding to the end of the element A3 to which the conductor A2 is connected, is connected by a conductor A! to the negative side of the battery I. It will thus be seen that the fire circuit A is a closed circuit including the relays 2, 3, the fire detecting cable l and the terminal resistance 4. The relay 3 is such that it is normally actuated and due to the resistance 4 the relay 2 is normally inoperative. The elements A3 and A6 of the fire detecting cable are juxtaposed normally insulated electrical conductors one of which upon the existence of abnormal thermal conditions fuses and becomes electrically connected to the other thus shunting the resistance 4. When this condition exists the resistance 4' is shunted out of the circuit and sufficient current flows through the relay 2 to actuate this relay. The same condition may be obtained by the actuation of a manual fire box represented diagrammatically'at 5. This fire box is connected across the terminals of the cable 4 and when actuated connects these two terminals together, thus shunting out the resistance 4 and effecting the operation of the fire relay 2. If anything occurs which opens the circuit A, the relay 3 is deenergized. Deenergization of this supervisory relay 3 effects, through the contacts thereof, the operation of local trouble signals on the protected property either audible or visual or both and a transmitter. The manner in which the operation of the local trouble signals is effected is illustrated in the copending application Serial No. 687,278, filed August 29, 1933, and the manner in which the operation of the transmitter is efiected will be hereinafter described.

When the fire relay 2 is operated it completes, through contacts 2a and 2b thereof, a circuit to an electrically actuated, mechanically operated transmitter 6 mounted on a control panel. This circuit B includes a conductor AI which connects the positive side of a thirty-two volt battery I to the movable contact 2a which is actuated by the relay 2 and which cooperates with the fixed contact 2b. The contact 21) is connected by a Wire B2 to one side of the coil 6a of the transmitter 6. The other side ofvthe coil 60. is connected by a wire B3 to a movable contact 62' of the transmitter 6 which is controlled by the relay coil 6a. The movable contact 62' cooperates with a fixed contact 67' which is connected by a wire B4 to a negative line wire B5 that is connected in common to the negative terminals of the thirtytwo volt battery I and a six volt battery I. In addition to the fixed and movable contacts 62' and 6?, the relay 6 has other cooperating fixed and movable contacts 6?) and 6c, 6d, 66 and 6), and and By and 6h the purpose of which will hereinafter appear.

A supervising relay 8 is connected across the terminals of the thirty-two volt battery I and it is normally energized. One side of the relay is connected to the positive side of the battery by a wire C3 and the other side of the relay winding is connected to the negative side of the battery by a wire C4. If for any reason the battery fails and there is not sufficient power for operating the system, the relay winding 8 becomes deenergized and the fixed and movable contacts 8a and 8b thereof are closed. The fixed and movable contacts 8a and 8b are connected into a circuit which controls the energization of a transmitter 9. This circuit D includes a conductor DI connecting the movable contact 8b to the positive side of the six volt battery I, and

a conductor D2 connecting the stationary contact 8a, to one side of the coil 9a of the transmitter 9. The other side of the coil of the transmitter 9 is connected through a conductor D3 to a movable contact 92' of the transmitter which contact is actuated by the coil 9a and cooperates with the fixed contact 97'. The fixed contact 97' is connected by a conductor D4 to the negative line wire B5 and thus to the negative side of the battery 'l'. Upon failure of the thirty-two volt battery l, therefore, the six volt battery I supplies a current to the coil 9a of the transmitter 9. This current is sufficient to actuate this transmitter. The transmitter includes in addition to the contacts 92 and 97', fixed and movable contacts 9b and 9c, 9d, 9e and 9i, and 99 andSh which are all actuated by the coil 9av of the transmitter and the purpose of which will hereinafter appear.

As heretofore stated, the supervisory relay 3 becomes deenergized when the fire circuit is opened, that is, when such a condition exists that would render the fire circuit inoperative for detecting abnormal thermal conditions, and effecting the operation of the signals. This relay includes a pair of cooperating movable and fixed contacts 30 and 3b which control the energization of a transmitter it. The contacts 3a. and 3b are normally separated by the energization of the relay and maintain a circuit E open. The circuit E includes a conductor El which connects the movable contact 3a to the positive side of the thirty-two volt battery I, and a conductor E2 which connects the stationary contact 3b to one side of the coil lfia of the transmitter l0. Thus when the contacts to and 3b are closed by virtue of the deenergization of relay 3, the coil Illa of the relay is connected to the positive side of the thirty-two volt battery. The other side of the coil lllct of the relay l is connected to the negative side of the battery through a conductor E3, a movable contact llli of the transmitter ID, a stationary contact llly' contacting with the contact Elli and a conductor E4 which connects the stationary contact Illa to the negative wire B5. The contacts I02 and H37 are normally closed and are opened upon the energization of the relay coil ma. This arrangement effects an intermittent operation of the relay. In addition to the contacts lei and H37, the relay ll] includes cooperating stationary and movable contacts lllb and tile, and llld, llle andlllf, and I09 and lllh. These latter cooperating contacts control circuits which will hereinafter be described. It will be evident from the description of this circuit that upon deenergization of the relay 3, that is, upon a break existing in the local system within the protected property which is detrimental to the proper operation of the fire circuit, the transmitter it is operated.

One of the effects of the operation of the transmitter in is the operation of a remote trouble bell H. The local trouble signals on the protected property are normally grouped together in a place where they are visible during the time the building is occupied. These trouble signals include all of the supervisory signals including the signals for trouble in the lights and other elements of the system. For example, in a school, these trouble signals would be located in the principals office. However, when the building is not occupied, there is no one at hand to respond to these trouble signals except the watchman or janitor. The remote trouble bell ll is therefore provided for indicating trouble which would impair the ability of the system to effect the operation of the signal in the fire engine house. The remote trouble bell H is therefore controlled by the transmitter ll] and the circuit for controlling this remote trouble bell through the transmitter ll] includes a conductor Fl, which connects. the stationary contact lllf of the'transmitter ll! to the positive side of the battery l through a resistance E2. The remote trouble bell, however, operates on six volts and the resistance I2 is thereforeprovided to cut down the voltage supplied to the trouble bell when it is actuated by the transmitter it. In the circuit F, the movable contact lllg is connected to a conductor F2 which is connected to one side of the remote trouble bell ll. The movable contact lllg is normally in contact with stationary contact lllh. This stationary contact lllh is connected through a conductor F3 to the movable contact 99 of the transmitter 9. The movable contact 9g is normally in contact with the stationary contact 9h which is connected by a conductor F4 to one side of the coil of a relay is. The relay l3 is connected to the conductor F4 through a resistance M which cuts down the current normally sup plied to the coil of the relay. The other side of the coil of this relay is connected through a conductor F5 to the positive wire Fl. A conductor F3 connects the trouble bell ll to the negative line wire 135. It will be apparent from this description that there is a closed circuit through the trouble bell and relay winding l3 as follows: positive terminal of the thirty-two volt battery, conductor Fl, conductor F5, the coil of relay l3, resistance M, conductor F4, stationary contact lift of transmitter 9, movable contact 9g, conductor F3, stationary contact lllh of transmitter l0, movable contact lug, conductor F2, remote trouble bell l l, conductor F6, and nega-- tive conductor B5 to the negative side of the thirtytwo volt battery. The resistance of this circuit is such that the current flowing there through is insufficient to operate the bell ll. It it, however, sufficient to energize the relay winding l3. Upon the actuation of the transmitter l-ll, however, thecontact lllg is moved into engagement with the contact lllf thus connecting the wire F2 to'the positive side of the thirty-two volt battery through the resistance l2. There is i then a direct circuit through the remote trouble bell which causes that bell to be actuated, the relay winding l3 being opened. This circuit includes the thirty-two volt battery, the wire Fl connecting the positive side thereof, resistance l2, stationary contact lllf, movable contact lllg, wire F2, remote trouble bell ll, wire F6 and negative wire B5. thus actuated upon the operation of the transmitter ill.

The remote trouble bell is also actuated upon the operation of the transmitter 9. When the transmitter ll is operated, the movable contact 9g is separated from the stationary contact 9h and brought into engagement with the stationary contact 9). The stationary contact 9) is connected through a wire F7 to the positive side of the six volt battery. Consequently, when the transmit- 'ter operates and the contacts 9g and 9) are brought together, there is a direct circuit through the trouble bell and the six volt battery which is as follows: the positive side of the six volt battery, wire Fl, contact 9; of transmitter 9, movable contact to, wire F3, stationary contact lflh of transmitter I ll, movable contact lllg of transmits tor ll wire F2, remote trouble bell II, and wire The remote trouble bell is F6 to the common negative line wire B5. Thus, the remote trouble bell is also actuated when there is a failure of the thirty-two volt battery.

The closed circuit described above which includes the remote trouble bell is a supervisory circuit. As heretofore stated, if this circuit is opened for any reason such as the breaking of a conductor or an open circuit in the trouble bell, the relay i3 is deenergized. This relay controls a set of fixed and movable contacts I 3a. and 13b which. are. in the circuit of a trouble lamp M which upon being illuminated indicates that there is trouble in the remote trouble bell circuit. The circuit to the trouble light includes the conductor Fl which is connected to the positive side of the battery, the conductor F5 connecting the conductor Ft to one side of the relay 13, a conductor Gl connecting the movable contact 13a of the relay iii to the conductor F5, a conductor G2 connecting the stationary contact l3b to the trouble light is and a conductor G3 connecting the trouble light to the common negative conductor B5. It will be obvious that upon the deenergization of the relay l3 and the engagement of the contacts iSa and 5311 the trouble light [4 will be connected across the thirty-two volt battery. Obviously this relay can also be used to operate an audible signal in addition to the visual signal represented by the light l4.

In conjunction with the transmitters 6, 9 and ie, there is a transmitter l5 which is manually operated and preferably mounted on the outside of the building protected by the system. The transmitter 15 is a code transmitter similar to transmitter G in that it transmits a series of impulses in accordance with the predetermined code. The code may also include an added elenent or impulse to indicate to the fire departmentthat the call has been initiated by the outside transmitter. It is advisable, in these systems, to let the fire department know whether it is an outside or inside call. If it is an inside call then they can determine the exact location of the call from the panel board, particularly if the building protected is divided up into a series of zones. The transmitter l5 includes a pair of normally open stationary and movable contacts I5a and IE1). These contacts are successively closed and opened in accordance with a predetermined code when the transmitter is manually set into operation. The movement of the movable contact I5b to close and open the circuit is accomplished through spring wound motor, not shown. Across the contacts lea and !5b there is connected a resistance l5c.

The transmitter [5 forms in effect the end of a transmission line circuit extending from the protected property in which the several transmitters 6, t and ID are located to the fire engine house serving the locality in which the protected property is located. This transmission circuit is a closed circuit and includes a twelve volt battery it as a source of electrical energy. The twelve volt battery is located in the fire engine house and is connected to terminals Ilia and I6b on a panel E? which is also located in the fire engine house and mounted in a place where it is readily visible. The positive terminal 5a is connected through a wire HI to a connector I8a to which is also connected one end of a transmission line wire H2. The other end of the transmission line wire is connected to the contact 6b of the transmitter 6. A branch conductor H3 connects the line wire H2 to the contact lllb of the transmitter iii. The movable contact 100 which cooperates with the stationary contact Ill?) and which is normally in engagement therewith is connected by a conductor H4 to the stationary contact 92) of the transmitter 9. The movable contact of the transmitter 9 which normally engages the fixed contact 9b is connected through a conductor H5 to one side of the code transmitter IS. The other side of the code transmitter I5 is connected by a conductor H6 to the fixed terminal 61 of the transmitter B. The fixed contact 6 of the transmitter 6 is normally in contact with the movable contact 6e which is connected by a conductor Hi to one end of the transmission line wire H8 which is connected in common to the movable contacts 60 and Be of the transmitter 6. The transmission line wire H8 connects these contacts to a contact Hill on the panel H in the fire engine house. The contact i8b is connected through a wire H9 to one side of the coil of a relay H). The other side of the relay is connected through a wire Hi6 to one side of the coil of another relay 2!). This latter relay is connected through a wire HI I to a negative line wire Hi2 which is connected to the negative terminal lfib. It will thus be apparent that there is a closed circuit including the transmission line wires as follows: battery terminal lfia, positive line wire Hi, terminal l8a, transmission line wire H2, conductor H3, fixed and movable contacts [0b and We of transmitter H conductor H4, fixed and movable contacts 917 and So of transmitter 9, conductor H5, resistance I50 connected across the terminals I50 and l5b of transmitter 55, conductor H6, normally closed fixed and movable contacts 61 and lie of transmitter 6, conductor I-Il, line wire H8, connector l8b, conductor H9, the coil of relay l 9, conductor H [0, the coil of relay 2!], conductor HI I, and negative line wire Hi2. The resistance 15c is sufficient to reduce the current in this circuit so that the relay 25 is normally not operated. The relay l 9 is however normally operated and controls circuits which will hereinafter be particularly described.

The transmitters (i and i5 operate intermittently shunt the resistance l 50 out of the circuit in accordance with predetermii d code, thus effecting the intermittent energization and deenergization of the relay 20. With the transmitter i5 this is accomplished by merely bringing together the contacts I511 and E51 It will be apparent that when these two contacts are connected together the wires H5 and H 5 are directly connected and the resistance ific is shunted out of the circuit. The same effect is obtained when the transmitter 6 is operated. The first thing that transpires upon the energization of the coil of transmitter 6 is that the contacts 6b and to close. Thereafter contacts 62 and 6] open and contacts 5e and 5d close, while contacts 513 and 5c are still closed. When the transmitter 8 is operated the transmitter 25 and resistance We are cut out of the circuit by the opening of contacts 5e and 6]. Upon the opening of contacts 62) and 5c, the circuit including the line wires H2 and H8 is therefore completed through a resistance 2! so as not to leave the circuit open. The closed circuit is then through the contacts o and 6.52 as follows: line wire conductor H3, res ance 2! which is connected between COIld'LlC or H3 and contact lid, movable contact wire H? and wire H8. The transmitter 55 is out out of the circuit upon the operation of transmitter G to prevent any interference by it in the operation of the transmitter (5. The contacts 62' and 6 open and close in accordance with the operation of the transmitter and serve to restore the line upon the completion of the operation of the transmitter.

The operation of the transmitter 6 is effected electrically but the operation is continued mechanically, a spring motor furnishing the power.

When the transmitter is operated, the contacts Eh and to are closed. These contacts close a circuit to a light 22 which indicates that the transmitter should be rewound. This light remains lighted until the transmitter has been revvound and placed in condition for repeated operation. The circuit to the light includes a wire I l. which is connected to the wire Fl which as heretofore described is connected to the positive side of the thirty-two volt battery. Wire II is also connected to the movable contact 6h. Thus, upon the closing of the contacts 6h and 69, contact 69 is connected to the positive side of the battery. The contact 60 is connected to one side of the light 22 by a wire I2, and the other side of the light 22 is connected by a wire I3 to the negative line wire B5.

The transmitter Ill when actuated causes a series of intermittent successive openings and closings of the transmission circuit. The opening and closing of this circuit is accomplished through the normally closed contacts lflb and lllc which as heretofore described, form a part of the circuit connecting the conductors H3 and H4.

" When the circuit is opened and closed, it effects the successive deenergization and reenergization of the relay IS. The transmitter Ill which is operated by a spring motor also includes a rewind signal light 23. This rewind signal light is connected in a circuit which includes the wire Fl operation.

The transmitter 9 is identically the same as the transmitter I0. In the transmitter 9 the normally closed fixed and movable contacts llb and He are, as heretofore described, connected in series in the transmission circuit H. Upon the operation of the transmitter these contacts are opened and closed intermittently. The opening and closing of the contacts do not follow any particular code but merely consists of successive separations and engagements of the contacts. Like the transmitter It, the transmitter 9 includes a Signal light 24 for indicating that the transmitter has been operated and should be re wound. The circuit for this signal light includes the fixed and movable contacts 9d and 9c of the transmitter 9. The movable contact 9c is connected to the Wire Fl which as heretofore described is connected to the positive side of the six volt battery, the contactors 9e and 9 being connected in common to the wire F1. The stationary contact 9d cooperating with the movable contact 9c is connected by a conductor K! to one side of the light 24. The other side of the light 24 is connected by a conductor K2 to the negative line wire B5. Upon the operation of the transmitter contacts 9d and ae are brought into engagement and the circuit to the light 24 is completed through the six volt battery. As heretofore described, this transmitter operates when the thirty-two volt battery fails. For this reason its rewind light is taken from the six volt battery by which the transmitter itself is operated.

The successive opening and closing of the circuit H and the intermittent shunting of a portion of the circuit efiect the operation of a series of relays including the relays I9 and 20 for" the purpose of operating several independent signals to indicate at the fire engine house trouble in the fire circuit of the protected property, failure of the thirty-two volt battery, and trouble in the transmission line extending between the protected property and the fire engine house. When either the transmitter 6 or IE operates to shunt out a portion of the resistance of the circuit H, the relay 20 is operated in accordance with the operation of the transmitter. Each time the contacts of the transmitters close and cut out the resistance, an impulse of current of sufiicient magnitude to operate the relay 20 passes through the circuit H and causes the full energization of the coil of this relay. When the contacts open the coil of the relay becomes partially deenergized and releases its movable contacts 200. and 2011. The cooperating movable and fixed contacts 20a and 20b of the relay 2!! are normally open and are closed when the coil of the relay 2!] is fully energized. These two contacts are included in a circuit to a relay 25 which controls the actuationof two gongs 26 and 27, one located in the fire engine house containing the panel H, and the other located elsewhere. The circuit to the relay 25 includes a positive line wire Ll which at one end is connected to the positive terminal IEO. on the panel I1. A conductor L2 connects the movable contact 28' of a relay 28' in the system ZZ to the line wire Ll. A cooperating fixed contact 28g of the relay 28 which is normally in engagement with the movable contact 28' is connected by a conductor L3 to a conductor L4 which is also connected to the movable contact 200. of the relay 2|]. Thus the contact 29ais connected to the positive side of the twelve volt battery. The fixed contact 201) is connected by a conductor L5 to one side of the coil of the relay 25. The other side of the coil of the relay 25 is connected by a conductor L6 to the negative conductor Hi2. When the relay 20 is fully energized and the contacts 20a and 2% are in contact a circuit is completed to the relay 25 as follows: positiveterminal Ilia, positive line wire Ll, conductor L2, movable contact 28' of relay 28, fixed contact 28g of relay 28', conductor L3, conductor L4, movable contact 2011 of relay 20, cooperating fixed contact 2019, conductor L5, relay 25 and conductor L6 to the negative conductor H! 2 and thus to the negative connector I 6b.

The relay 25 includes a pair of movable and fixed contacts 25a. and 25b and 25c and 25d. The cooperating movable and fixed contacts 25a. and 251) are in a circuit which includes the gong 26. This circuit includes a conductor Ml which connects the gong to the positive line wire through a gong connector 26a on the panel IT. The other side of the gong is connected through a connector 2% on the panel I! to a conductor M2 which is also connected to the fixed contactor 25b of the relay 25. The cooperating movable contactor 25a. is connected by a conductor M3 to the negative line wire Hi2. Upon the operation of the relay 25 the movable contact 25a engages the fixed contact 2512 and the circuit is completed from the battery IE to the gong 26 as follows: Line wire, wire Ml, gong 26. conductor M2, contact 251), contact 25a and negative line wire Hl2. A similar circuit includes the gong 27. This circuit consists of a wire NI connecting one side of the gong to the positive line wire through a connector 21a on the panel H. The other side of the gong is connected through a connector 21b to a conductor N2 which is also connected to the fixed contact 25d of the relay 25. The movable contact 250 cooperating with the fixed contact 25d is connected by anonductor N3 to the negative line wire H12. The gongs 26 and 21 are of course merely representative of audible signals and may be sirens or any other like signal. 2

The relay 20 also includes cooperating fixed and movable contacts 200 and 2901 which are normally separated and which are connected upon the full energization of the relay. These contactors are included in a circuit in which is included a relay 28 which controls a visual signal represented by a lamp 29. The circuit to the relay 28 includes the positive line wire Ll, a wire OI which connects the positive line wire Ll to the movable contact 2001, a wire 02 which connects the stationary contact 230 to one side of the relay 28, and a conductor 03 which connects the other side of the relay 28 to one terminal of a reset switch 30 which includes fixed and movable contactors 30a and 39b that are normally closed and included in the circuit to the relay 28. The conductor 03 is connected to the fixed contactor 39a of the reset switch, and the movable contactor 38b is connected through a conductor 04 to the negative line wire HIZ. When the relay 28 is thus energized it completes a holding-in circuit so that it remains energized irrespective of the subsequent deenergization of the relay 20. This holding-in circuit includes a conductor which is connected to a movable contact 280. The movable contact 280 cooperates with a fixed contact 28d which is connected to the conductor 02. Upon energization of the relay 28 the circuit through that relay is completed through the contacts 280 and 28d and is independent of the relay 29.

As heretofore stated, operation of the relay 28 effects the energization of the light 29 to provide a visual signal. This is accomplished in part through the operation of a fire lamp relay 3| which is energized upon the energization of the relay 28. The circuit for energizing this fire lamp relay includes a conductor Pl which connects the positive line wire Ll to a movable contact 28a on the relay 28. The movable contact is normally separated from a cooperating fixed contact 2812 to which it is connected upon energization of the relay. This fixed contact 281) is connected by a conductor P2 to one side of the coil of the relay 3|. The other side of the coil of the relay 3| is directly connected through a wire P3 to the negative line wire Hl2. It will be seen that this circuit to the relay 3| is closed upon the energization of the relay 28.

The relay 3| includes a movable contact 3| a which cooperates with two fixed contacts 3lb and 310. The fixed contact 3lb which is normally separated from the movable contact 3la is connected by a conductor QI to the negative line wire Hl2. The movable contactor which is connected to the fixed contact 311) upon energization of the relay is connected through a conductor Q2 to one side of the light 29. The other side of the light 29 is connected by a wire Q3 to a fixed contact 28c of the relay 28. This fixed contact cooperates with a movable contact 28 to which it is connected when the relay 28 is energized. The contact 28f is directly connected through a wire Q4 to the positive line wire LI. Thus, upon energization of the relay 28, the relay 3! is operated and through the closing of the contacts 286 and 28f of the relay 28 and the contacts Sid and 3| b of the relay (ii, the light 29 is energized and provides a visual signal indicating the origin of the fire. This signal it will be understood is individual to a particular property that is protected by the system YY and consequently affords a visual signal designating the location of the fire. The gongs operated in accordance with the code also designate the location of the fire by an audible signal which may be interpreted but the light 29 provides an immediate signal at the fire engine house wherein it is located and there is no necessity for the men to await the completion of the code on the audible signal. Since relay 28 is locked, the light also provides a continuous designating signal after the audible signal has become dormant.

As heretofore stated, the relay I9 is normally energized and becomes deenergized when the circuit H is opened. This relay includes cooperating fixed and movable contactors l9a and I 9b which are normally separated. Upon deenergization of the relay these contactors are connected and complete a circuit to a relay 32. The circuit to the relay 32 includes the negative line wire Hl2 and a conductor RI connecting the negative line wire to the movable contact 19b. The fixed contact I 9a is connected by a conductor R2 to movable contact 33a of another relay 33. This movable contact 33a is normally in contact with a fixed contact 33b which is connected by a conductorR3 to one side of the coil of the relay 32. The other side of the coil of the relay 32 is connected through a conductor R4 to the positive line wire LI and to the positive terminal Ilia. Thus, when the circuit H is opened the coil of the relay 32 is energized.

The relay 32 has two pairs of fixed and movable contacts, 32a and 32b, 32c and 32d. One pair of these contacts, that is, contacts 32a and 32b, control a circuit to a trouble light 34. This circuit includes a conductor S! which is connected to the positive side of the twelve volt battery through the conductors R4 and LI to which it is connected, a conductor S2 connecting the conductor S! to one side of the trouble lamp, and a conductor S3 which connects the other side of the trouble light to the stationary conductor 32b of the relay 32. The cooperating movable contactor 32a of the relay 32 is connected through a conductor S4 to the conductor 04 and thus to the negative line wire Hi2. The circuit to the light is therefore completed upon the energization of the relay 32. This trouble light 34 indicates that there is trouble in the transmission line and that a signal can not be transmitted over the line.

The contacts 32d and 320 of the relay 32 are included in a circuit to a trouble bell 35 and upon contacting when the relay 32 is energized complete the circuit to the trouble bell so that there is an audible as well as a visual signal indicating trouble in the transmission line. The circuit to the bell includes a conductor Tl which connects one side of the bell to the conductor Si and thus to the positive side of the twelve volt battery, a conductor T2 which connects the other side of the bell to the stationary contact 32c of the relay 32 and a conductor T3 which connects the cooperating movable contact 32d to the conductor S4 and thus to the conductor 04 and the negative line wire Hi2. It will be apparent, therefore, that on the energization of the relay 32 both the visual signal 34 and the audible signal 35 are actuated.

If the transmission circuit H is opened and closed in accordance with the operation of either of the transmitters 9 or iii, the relay I9 is successively deenergized and energized in accordance with the intermittent operation of the transmitter. When the relay I9 is deenergized, in addition to completing the circuit to the relay 32 it completes a circuit to a relay 36. This circuit to the relay 33 includes a wire U! which connects a movable contact We on the relay I9 to the positive line wire LI. The contactor I 9e cooperates with a stationary contact I9 from which it is normally separated but with which it is connected upon the deenergization of the relay E3. The contactor I91 is connected by a conductor U2, which has an interposed resistance 3i, to one side of the relay 36. The other side of the relay 35 is connected by a conductor U3 to a stationary contactor 300 of the reset switch 33. The contact 300 cooperates with a movable contactor 3311 which is connected by a conductor U 5 to the wire 04 and thus to the negative line wire L1. The relay 3B is thus connected through the reset switch in a closed circuit upon the deenergization of the relay I9. Upon energization of the relay 36, the relay closes a hold-in circuit which includes a conductor U5 that connects a movable contactor 33st to the conductor R4 and thus to the positive side of the battery. The conductor U2 has connected thereto a stationarycontactor 360 which engages the movable contactor 36d when the relay 36 is energized. The relay 36 then becomes independent of the action of the relay I9.

The relay 36 also includes a pair of movable and fixed contactors 33a and 3% which control a circuit to a reset light 33. This circuit includes the conductor Si which is connected to the positive side of the battery, a conductor Vi which connects the conductor SI to one side of the light 33, and a conductor V2 which connects the other side of the lamp to the stationary contact 33b of the relay 3'5. The cooperating movable contact 33a which engages the contact 36b upon energization of the relay 33 is connected by a conductor V3 to a conductor S4 which in turn is connected to the conductor 04 and thus to the negative line wire Hi2. The reset lamp is thus lighted to indicate that the relays have been operated and should be reset. The contacting of contacts 33a. and 33b of relay 36 also connects a conductor WI to the wire V3 and thus to the negative side of the battery. The conductor WI is also connected to a movable contactor liic which cooperates with a fixed contactor 13d. of the relay I9. Upon the reenergization of the relay I9 the circuit to the relay 32 is broken. Thus this relay becomes deenergized and also the trouble light 34 becomes deenergized.

On the reenergization of the relay I9 by the successive opening and closing of the circuit H the contactor We of the relay I9 which is now connected through the contacts 36b and 36a of relay 33, energized through its hold-in circuit, and the conductor V3 to the negative side of the battery, engages the contactor IQcZ of the relay I9. This latter contact is connected through a conductor W2 to one side of the coil of the relay 33. The other side of the coil of the relay 33 is connected to the conductor R4 and thus to the positive side of the battery. It will therefore be evident that upon the reenergization of the relay I9 the relay 33 becomes energized. This relay upon becoming energized closes a hold-in circuit which includes fixed and movable contacts 33e and 33 of the relay 33. The contact 33f is directly connected to the conductor W2, and the stationary contactor 336 is connected by a conductor W4 to the wire U3 and thus through the reset switch to the wire 04 and the negative side of the battery. The closing of the contactors 33c and 33] therefore renders the energization of the relay 33 independent of the relay I9. Upon the energization of the relay 33 contacts 33a and 33b thereofare opened and thus prevent the completion of the circuit to the relay 32 upon the relay I3 becoming again deenergized in acordance with the intermittent op eration of either transmitters 3 and Ii]. Thus, upon the successive opening and closing of the circuit H, the relay 32 is deenergized preventing the operation of the trouble light 34.

However, upon the operation of relay 33 a trou ble light 39 is energized to indicate that there is trouble in that portion of the system within the protected property. The circuit to this tron ble light includes a conductor X! which is connected to the conductor SI and thus to the positive side of the battery, the light 33 to which the conductor Xi is also connected, a conductor X2 which connects the lamp to a stationary contactor 33d on the relay 33, a movable contactor 330 which cooperates with the contactor 33d and engages this contactor when the relay is energized, and a conductor X3 which connects the movable contactor 330 to the conductor V3 and thus the conductor 04 and negative line wire HIE. The stationary and movable contactors 33g and 33h of the relay 33 serve upon being engaged by the energization of the relay to complete a'circuit to the trouble bell 35. This circuit includes the wire Ti through which one side of the trouble bell is connected to the positive side of the twelve volt battery, the conductor T2, and a conductor T4 which connects the conductor T2 and the stationary contactor 33g. Movable contactor 3371. is connected by a conductor T5 to the conductor V4 and thus to the conductor 03 and the negative line wire Hi 2. The operation of the relay 33 by the successive deenergization and reenergization of relay i3 effects through these circuits the operation 01 the trouble bell 35 and the trouble light 39, the trouble bell indicating audibly that trouble exists in the system, and the trouble light definitely locating the trouble to be in that portion of the system located upon the protected property.

It is to be noted that the relays 28, 33 and 36 when operated are connected to the source of energy, that is, the twelve volt battery, through the reset switch 33. After the trouble in the line has been located or the fire extinguished, the reset switch is manually actuated so that the movable contact 30d is separated from the movable contact 336 and the movable contactor 33b is separated from the stationary contact 33a thus breaking the circuits to these three relays. When the circuits are broken to these relays they become deenergized and restored to their normal or original position. When this is done the restore light controlled by relay 36 is extinguished. The restore light 33 indicates that one or the other of these relays 33 or 33 are operated.

It is also, in effect, a secondary supervisory light for the trouble lights 34 and 39 or a trouble light ancillary to the trouble lights 3 and 39 for if this restore light lights independently of the lights 34 and 39 it indicates trouble with the system and that one or the other of the trouble lights is inoperative.

Any number of similar systems may be used to protect various different properties. The systems for several such properties will be identical with that described immediately above. Several of such systems in a single locality will, however, be interconnected so that a single system of 'gongs will be actuated in common by the several circuits and several parts of the systems will be supervised in common. For the purpose of illustrating this interconnection, the illustrated embodiment of the invention includes the duplicate system ZZ on the panel at the fire engine house. The duplicate system ZZ includes the circuits H, I, J, etc. which are identical with the correspondingly designated circuits H, I, J, etc. of the system YY. The circuits of the system ZZ at the protected property have not been illustrated as there is no interconnection between this portion of the system. The circuit at the protected property for the circuit H of system ZZ may be identical with that shown for the operation of the circuit H.

Since in a group of systems the single stroke gongs 26 and 2'! are common to the several systems, it is necessary in order to prevent a jumble of the code signals by the simultaneous operation of both systems, to provide means for cutting out control of the gongs by all other systems when one system operates. In the system illustrated this is accomplished through the contacts 28') and 28g of the relay 28'. The systems are arranged in accordance with the possible fire hazard in the properties which they protect. In the illustrated case the system ZZ operated by the circuit H is a greater fire hazard than the system YY. This system therefore is given preference over the system YY. Therefore the contactors 28g and 28' of the relay 28' control the connection of the contact 20a of the relay 20 which on engaging the contactor 20b,

operates the gong relay 25. When the relay 28 operates, upon operation of relay 20 the movable contact 28'f is separated from the stationary contact 28'g thereby cutting the movable contact 200. of the relay 20 oil? from the conductor L2 and thus the positive side of the battery. The movable contact 28'f is on the other hand brought into contact with another stationary contactor 28e of the relay 28. This contactor 28e is connected by a conductor Y! to the movable contact 20'11v of the relay 20 thus connecting this movable contact to the positive side of the battery and rendering it ready to complete the circuit to the gong control relay 25, the stationary contact EQb being connected to the wire L5 in common with the stationary contact 202) of the relay 29.

It is to be noted that it is only the control of the gong that is taken from. the system YY upon the operation of the system ZZ. The fire lamp 29 is however operated so that there is a visual indication of a fire on the property protected by the system'YY even though the system ZZ has control of the gong for sending an audible code signal.

The control circuit or the circuit for preventing interference is supervised so as to indicate a condition which would prevent any of the interconnected'systems from operating normally. This supervisory circuit includes a supervisory relay 4!] which is connected in series with the contacts 28' and 28'g of the coil of the relay 28. The circuit to the relay includes the conductor L2, movable contact 28' the stationary contact 28'g, conductor L3, coil of the relay it, and conductor Hi2. There is thus a complete circuit through the battery It and the coil of the relay 4i) and this relay is normally energized. The relay d8 contains two pairs of fixed and movable contacts Mia and 5th and 4:50 and 40:1. The contacts 48a and 4% are in a circuit which includes the trouble bell so that when the coil of the relay becomes deenergized as, for example, by the accidental opening of the contacts 28') and 28g, a circuit is completed to the trouble bell 35 which is operated to give an audible trouble signal. The circuit to this trouble bell includes a conductor ZI which is connected to the negative line wire Hi2, a movable contact 3ld on the relay 3!, a fixed contact 3| e of the relay 3i which is normally in engagement with the movable contact 35d and a conductor Z2 which connects the stationary contact 3| e to the movable contact llld of the relay 40. The cooperating fixed contact 40c of the relay 40 is connected to a conductor Z3 which is connected to the conductor T2 which latter conductor is, as heretofore described, connected to one side of the trouble bell 35. It will be apparent that upon operation of the relay ii the side of the trouble bell to which the Wire T2 is connected will be connected to the negative side of the twelve volt battery. The other side of the trouble bell is, as heretofore described, permanently connected to the positive side of the battery. Thus the operation of the trouble bell is effected upon the deenergization of the relay 46. It is to be noted that the operation of the trouble bell is dependent upon the continued inoperation of the fire lamp relay 3!. When this is operated the circuit connecting the movable contact 40d to the negative side of the battery is broken at the contacts 31d and 35c. In the event of an actual fire operating the relay 28 and the relay 3|, the trouble bell will not be operated due to a break in the circuit to the relay 40.

In addition to the audible trouble bell 35, a visual signal 4| is energized and specifically indicates trouble with this non-interference circuit. The circuit to the lamp 4| includes the conductor Zl, the contacts Md and 31c of the relay 3|, the conductor Z2, and a conductor AAl which connects the conductor Z2 to the movable contact 402) thus connecting the movable contact 40b to the negative side of the twelve volt battery. The stationary contact 40a cooperating with the movable contact 4% is connected by a conductor AA2 to one side of the light M and the other side of the light 4| is connected by a conductor AA3 to the positive line wire SI and thus to the positive side of the battery. It will therefore be apparent that upon the engagement of the contacts 40a and 40b while the relay 3! remains deenergized a circuit through the lamp 4| and the battery [2 will be completed thus lighting the light and providing the specific visual signal.

Electrical supervision is also provided for the gongs 26 and 21. The supervisory circuit for the gong 26 includes the positive line wire HI, the conductor Ml connecting the connector 26a, the gong 26, the connector 26b. conductor M2,

a conductor ABI which connects the conductor M2 to one side of the coil of a supervisory relay 42, and a conductor AB2 which connects the other side of the coil of the supervisory relay 42 to the negative line wire Hi2. This is a complete closed circuit through-the gong Z6 and the relay 42 and including the battery iii. If this circuit is open for any reason the relay 42 becomes deenergized. r l

The relay 42 upon becoming deenergized permits the contacting of two pair ,of' fixed and movable contacts 42a and 42b and 420 and 4212. The fixed and movable contacts 520 and 42d are in a circuit which includes the trouble gong 35. This circuit includes the conductor M3 which connects the movable contact a of the relay 25 to the negative side of the battery, a contactor 25c which normally engages the movable contactor 25a and a conductor ACI which connects the stationary contact 258 of the relay 25 to the movable contactor 42d of the relay 42. The contact 420 which cooperates with the contact 42d is connected to the conductor Z3 and thus to one side of the trouble bell as heretofore described. Upon the engagement of the contactors 42d and 420 while the relay 25 is inoperative, the wire Z3 is connected to the negative side of the battery and as a consequence completing a circuit through the common trouble bell. The contacts 42a and 4221 are connected into a circuit with a trouble light 43 which is illuminated upon the deenergization of the relay 42. This circuit includes the conductor M3, the movable and fixed contacts 25a and 25a of the relay 25, the conductor ACI, a conductor ADI which connects the movable contact 42b with the conductor ACI, a conductor ADZ which connects the fixed contact 42a, with one side of the light 43 and a conductor AD3 which connects the other side of the light to the conductor AAS and thus to the positive side of the battery. The light 43 and the trouble bell 35 furnish audible and visual trouble signals upon the opening of the gong circuit. The audible signal calls the attention of any one in the vicinity to the fact that trouble exists in the system and the visual signal definitely locates the circuit in which the trouble exists.

A similar supervisory circuit is used for supervising the gong 2?. This circuit includes a relay 42 and a trouble light 43'. The connections through this latter relay are similar to those described in conjunction with the gong 26 and are similarly marked, the characters for desighating the latter circuit are primed to distinguish them from the former.

'The fire lights 29 and 251 of the systems YY and ZZ respectively, which are energized upon the existence of a fire or the coming in of a fire signal, are electrically supervised. The lights of the systems YY and ZZ are interconnected for the purpose of this supervision and the supervisory circuit includes both of these lights and a supervisory relay 44. This supervisory relay includes the conductor Ll which is connected to the positive side of the twelve volt battery It, a conductor AEI which connects the conductor Li and one side of the relay 44, a conductor AEZ which connects the other side of the relay 44 and the conductor Q3 which is connected to one side of the fire light 29, the conductor Q2 which connects the other side of the light 29 to the movable contact 3m of the fire lamp control relay 3!, a conductor AE3 which connects a stationary contact 340, which cooperates with the contact 3Ia and is normally in engagement therewith, to theconductor Q3 of the system ZZ which is connected to one side of the light 29" and the conductor QZ which connects the other side of the light 29 to the negative line wire HIZ. The several conductors, contactors, relays and lights form a normally closed circuit including the battery It which circuit is openedupon the actuation of the relay 3|. This closed circuit provides a supervisory circuit'including' the normally energized relay 44. j Upon the existence of any trouble in this circuit the relay 44 becomes deenergized and upon being deenergized effects the operation of the common trouble bell 35 and a distinctive trouble light 45. The circuit to the trouble bell includes the conductor 2!, the normally closed fixed and stationary contacts 31d and 3|e of the relay 3|, the conductor Z2, a conductor AF! which connects the conductor Z2 and a movable contact 44d of the relay 44, which cooperates with a fixed contact 440 which is connected in common to the conductor Z3 with the contacts 400, 42c and 420. As heretofore described the connection to the conductor Z3 to-the conductor Z2 completes a circuit through the trouble bell 35 which effects the operation of that bellf The audible signal is therefore effected upon the deenergization of the relay 44. Similarly, the light 45 is lighted. The circuit to this light includes the connection with the negative side of the battery including the conductors ZI and Z2 and the conductor AM, a conductor AGI which connects the conductor AFI to a movable contact 441) of the relay 44 that cooperates with a fixed contact 44a, a conductor AG2 which connects the stationary contact 44a with one side of the light 45 and a conductor AG3 which connects the other side of the light to the positive conductor AA3. Through this circuit the trouble fire lamp is also lighted upon the deenergization oi the relay 44 giving a visual signal which designates the exact circuit in which the troubleoccurred, that is, the circuit including the fire lamp. It will be observed that the filaments of the fire lamps are supervised by this circuit as the circuit includes these filaments. Consequently, if a filament is broken or burns out the trouble signals are operated. The resistance of the supervisory circuit is such that the filaments are not heated by the current flowing therethrough. A six volt battery 46 is provided for supervisory purposes. This battery is connected to terminals 46a and 4619 on the panel [1. The six v volt battery provides among other things the current for operating the signals upon the fail-' ure of the twelve volt battery. The twelve volt battery is supervised by a supervisory relay 41 which is connected across the battery through a conductor AHI and a conductor AH2. The

conductor AHI is connected between the relay and the positive line wire HI, and the conductor AHZ is connected between the relay and the negative line wire HI 2. This relay controls a trouble light 48 and a trouble bell4'9, the relay having two sets of fixed and movable contacts 41a and 41b which control the light 48 and 410 and 4111 which control the trouble bell 49. The contacts are normally open and become closed upon a reduction of the current to such an extent that the relay 4! becomes for all practical purposes deenergized. The circuit through the contacts 41a and 41b and controlling the light 48 includes a conductor AI! which connects the movable contact 411) to the conductor Z2 which, as herelight 5|. "in commonto theconductor Z2 and the stationtofore described, is connected through the contacts 3ld-3le of relay 3! to the negative wire. This negative wire is connected in common with the negative side of the six and twelve volt batteries. The stationary contact 41a is connected to one side of the lamp 48 through a conductor AH and the other side of the lamp is connected through a conductor A13 to the positive side of the sixvolt battery. It will therefore be apparent that upon the deenergization of the relay 4'! and the engagement of the contacts 41a and 411) the lamp 48 is connected across the six volt battery; The circuit to the trouble bell 49 includes the conductor All to which the movable contactor 41d of the relay 4! is connected in common with the movable contactor 41b. The stationary contact 410 is connected by a conductor AJ I to one side of the bell 49 and the other side of the bell is connected to the conductor A13 and thus to the positive side of the battery. The lamp 48 and the bell 49 operate on six volts and they give an audible and visual indication that the twelve volt battery supplying power for the various relays in the systems is inadequate to effect the operation of the systems.

In order to insure the immediate operation of the signals indicating'the failure of the twelve volt battery, the six volt battery'is also supervised. The supervision of this battery is accom plished through a relay 50 which is connected across the battery through a conductor AKI that connects one side of the relay with the conductor A13 and a conductor AKZ which connects the other side of the relay to the common negative conductor HI. The relay 5!), like the relay 4'! supervising the twelve volt battery, has two pairs of fixed and movable contacts 50a and 50b and 500 and 50d. The movable contact 500 of the relay 50 is connected to the conductor Z2 in common with the movable contactors of the relay 40. This contact 500 is therefore connected to the negative line wire Hi2. The cooperating fixed contact 5011 is connected in common with contacts of other supervisory relays to the conductor Z3 and thus to one side of the trouble bell 35, the other side of which is permanently connected to the positive side of the twelve volt battery. Through these contactors 50c and 50d the relay 50 may effect the operation of the trouble bell when the relay is deenergized. The contacts 50a and 50b are included in a circuit with a trouble The movable contact 50b is connected ary contact is connected to one side of the lamp 5| by a conductor ALI. The other side of the lamp 5| is connected by a conductor ALZ to the conductor AA3 and thus to the positive side of the twelve volt battery. The circuits just described are completed upon the deenergization of the relay 50 due to the failure of the battery 46. Upon the completion of these circuits, the common trouble bell 35 is sounded and the particular trouble light 5| designating the particular source of trouble is lighted.

It is to be noted that the operation of the trouble signals is dependent upon the continued inaction of the relay 25 or 3| which controls the warning signals.

From the above description of the illustrated systems it will be apparent that distinctly different warning and trouble signals are transmitted over a single pair of lines to a remote point and this pair of lines is electrically supervised such that when it is injured, a distinctly difierent signal from any of the signals transmitted over the line is operated to indicate this trouble. The value of being able to use a single pair of wires for the transmission of these signals and to supervise this transmission line will be readily apparent to those skilled in the art, the economy of installation being the predominant feature and the reduction in the possibility of trouble being another dominant feature. While within the property protected by the system herein disclosed, there may be numerous warning signals and devices as disclosed in the aforementioned copending applications which are also under electrical supervision, trouble with these devices which are inherently local in the system to the protected property is not transmitted to the remote point. If the protected property is occupied, trouble in the inherently local devices will be registered at the property and can be there corrected. If the building is unoccupied it is immaterial whether these inherently local warning and signaling devices are operated, for they are principally for the purpose of providing an immediate and orderly evacuation of the building.

It is obvious that various changes may be made by those skilled in the art in the details of the system illustrated in the drawings and described immediately above within the principle and scope of the invention as expressed in the appended claim.

I claim:

In electrical signal systems, a source of electrical energy, a plurality of systems each including two signals distinctive to each system and a third signal common to the several systems, each signal being adapted upon operation to indicate the existence of a particular condition, and each system including a means for eifecting the operation of each signal independently comprising a closed electrical circuit including a source of electrical energy, electrically actuated means operative upon opening the closed circuit for effecting the connection of the first mentioned signal to the source of energy, other electrically actuated means operative upon the successive opening and closing of the closed circuit for efiecting the connection of said second mentioned signal to the source of energy and additional electrically actuated means operative upon shunting a portion of the circuit for effecting the connection of the common signal to the source of energy, and means associated with one of said systems operative upon the operation of said last mentioned means for rendering the other control circuit ineffective to effect the operation of the common signal.

WILLIAM D. LINDSEY. 

